Determining device locations based on random access channel signaling

ABSTRACT

A user equipment (UE) device may determine its location with a high degree of precision, beyond the capability of other current methodologies. Specifically, a UE device may obtain High Precision (HIP) coordinates of its location based on Random Access Channel (RACH) messages that the UE device exchanges with multiple wireless stations. Using RACH messages to obtain HIP coordinates imposes little communication overhead or computational burden on the UE device and the network.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a continuation of, and claims priority to,U.S. application Ser. No. 16/146,544 filed Sep. 28, 2018, titled“Determining Device Locations based on Random Access Channel Signaling,”the contents of which are incorporated by reference herein in theirentirety.

BACKGROUND

User devices associated with a Long Term Evolution (LTE) network mayhave the capability to communicate via a Fifth Generation (5G) New Radio(NR) system. For example, an Evolved Universal Terrestrial Radio AccessNew Radio Dual Connectivity (EN-DC) device has the capability toexchange data with an LTE wireless station, as well as exchange datawith a 5G next generation wireless station. 4G user devices, 5G NRdevices, and other more advanced network-compatible devices may not onlybe capable of communicating with their networks at breakneck speeds, butmay also leverage their networks to provide services unavailable inother networks.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates concepts described herein;

FIG. 2 illustrates an exemplary network environment in which theconcepts described herein may be implemented;

FIG. 3 illustrates exemplary components of network devices included inthe network environment of FIG. 2 ;

FIG. 4 shows exemplary functional components of the user equipment (UE)device of FIG. 2 ;

FIGS. 5A-5C illustrate an exemplary process for determining HighPrecision (HIP) coordinates of the UE device of FIG. 2 based on RandomAccess Channel (RACH) signaling according to one implementation;

FIG. 6 is a messaging diagram illustrating an exemplary RACH procedurethat involves the UE device and a wireless station of FIG. 2 ;

FIGS. 7A and 7B illustrate exemplary structures of messages between theUE device and the wireless station of FIG. 2 ;

FIGS. 8A-8D illustrate an exemplary time delay associated with atransmitted message due to its traveling distance;

FIGS. 9A-9D illustrate an exemplary contention during a RACH procedure;and

FIG. 10 illustrates exemplary spheres.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The following detailed description refers to the accompanying drawings.The same reference numbers in different drawings may identify the sameor similar elements.

In implementations described herein, a user equipment (UE) device maydetermine its location with a high degree of precision, beyond thecapability of other current methodologies. More specifically, the UEdevice may obtain High Precision (HIP) coordinates of its location in4^(th) Generation (4G) networks, 5^(th) Generation (5G) networks, and/orother advanced networks based on Random Access Channel (RACH) messagesthat the UE device exchanges with three or more wireless stations.Because a UE device often exchanges RACH messages with wireless stations(e.g., when the UE device attempts to attach to a network or when the UEdevice is involved in a handoff), using RACH messages to obtain HIPcoordinates imposes relatively little communication overhead orcomputational burden on the UE device and the network. In addition, anetwork does not need to commit large amounts of resources to provideHIP coordinates to UEs in the network.

For a UE device, the precision of its HIP coordinates may depend on thesubcarrier spacing, a Fast Fourier Transform size of networktransceivers, and the number of wireless stations with which the UEdevice performs a RACH procedure to determine the HIP coordinates. Whilethe absolute precision of HIP coordinates may be limited by theprecision of the wireless station coordinates, the HIP coordinates of UEdevice may still be precise relative to the locations of the wirelessstations themselves and/or to HIP coordinates of other nearby UEdevices. The relative precision of HIP coordinates may be in centimeter(cm) or smaller ranges. Given their accuracy and precision, HIPcoordinates may be used for device navigation through intricatepassageways (e.g., guiding an unmanned aerial vehicle (UAV), anautonomous vehicle, etc.), for locating an item (e.g., an item in aretail store), improved accuracy for emergency response, etc.

FIG. 1 illustrates the concepts described herein. As shown, a system 100may include a UE device 102, a wireless station 104, and locationservice platform 106. UE device 102 and wireless station 104 aredescribed in greater detail with reference to FIG. 2 .

As shown in FIG. 1 , during normal operation, UE device 102 may monitorand receive broadcast messages from wireless station 104. The messagesmay include information that UE device 102 needs for attaching to anetwork (not shown). When UE device 102 is to obtain its HIPcoordinates, UE device 102 may use the information to exchange a seriesof messages with wireless station 104. As described below, UE device 102may use the messages to determine its HIP coordinates, rather thanrelying on a network-provided positioning service, such as a serviceprovided by location service platform 106.

FIG. 2 illustrates an exemplary network environment 200 in which theconcepts described herein may be implemented. As shown, networkenvironment 200 may include UE device 102, wireless stations 104-1,104-2, and 104-3 (generically referred to herein as wireless station 104and collectively as wireless stations 104), a provider network 202, anda packet data network 204. Depending on the implementation, networkenvironment 200 may include networks other than those illustrated inFIG. 2 . For simplicity, FIG. 2 does not show all components that may beincluded in network environment 200 (e.g., routers, bridges, wirelessaccess point, additional UE devices, etc.).

UE device 102 may include a wireless communication device. Examples ofUE device 102 includes: a smart phone; a tablet device; a wearablecomputer device (e.g., a smart watch); a global positioning system (GPS)device; a laptop computer; a media playing device; a portable gamingsystem; an Internet-of-Things (IoT) device. In some implementations, UEdevice 102 may correspond to a wireless MTC device that communicateswith other devices over a machine-to-machine (M2M) interface, such asLTE-M or Category M1 (CAT-M1) devices and Narrow Band (NB)-IoT devices.

Provider network 202, which may be operated by a Mobile Network Operator(MNO), may include a local area network (LAN), a wide area network(WAN), a metropolitan area network (MAN), an optical network, a cabletelevision network, a satellite network, a wireless network (e.g., aCDMA network, a general packet radio service (GPRS) network, an LTEnetwork (e.g., 4G network), a 5G network, an ad hoc network, a telephonenetwork (e.g., the Public Switched Telephone Network (PSTN) or acellular network), an intranet, or a combination of networks. Providernetwork 202 may allow the delivery of Internet Protocol (IP) services toUE device 102, and may interface with other networks, such as packetdata network 204. In some implementations, provider network 202 mayinclude one or more packet data networks.

Provider network 202 may include one or more wireless stations 104.Examples of wireless station 104 include evolved Node B (eNodeB) and 5GNode B (gNodeB). Wireless station 104 may be part of an access network(e.g., a radio access network, such as an evolved UMTS Terrestrial RadioAccess Network (eUTRAN)). The access network may provide UE device 102with wireless access to provider network 202.

Packet data network 204 may include a network that supports InternetProtocol (IP)-based communications. Packet data network 204 may include,for example, an IP Multimedia Subsystem (IMS) network, which may providevoice and multimedia services to UE device 102 based on SessionInitiation Protocol (SIP).

In FIG. 2 , when UE device 102 attempts to obtain its HIP coordinates,UE device 102 initiates, with each of wireless stations 104, a processfor attaching to provider network 202. The process maybe referred to asthe Random Access Channel (RACH) procedure. UE device 102 may performthe RACH procedure (or part of the RACH procedure, as described below)with each wireless station 104 to measure the distance from UE device102 to the wireless station 104, and apply the technique ofmultilateration to the measured distances to obtain its HIP coordinates.

To apply multilateration, UE device 102 may use at least three wirelessstations 104 with which UE device 102 can measure its distance thereto.If there are additional wireless stations 104, UE device 102 can obtainadditional distance measurements, and use the additional distancemeasurements to increase the accuracy of the HIP coordinates.

FIG. 3 is a block diagram of exemplary components of a network device300. Network device 300 may correspond to, or be included in, thedevices and/or components of the networks depicted in FIG. 2 (e.g., UEdevice 102, wireless station 104, a router, a switch, a server, etc.).As shown, network device 300 may include a processor 302, memory/storage304, input component 306, output component 308, network interface 310,and communication path 312. In different implementations, network device300 may include additional, fewer, different, or a different arrangementof components than the ones illustrated in FIG. 3 . For example, networkdevice 300 may include line cards, modems, etc.

Processor 302 may include a processor, a microprocessor, an ApplicationSpecific Integrated Circuit (ASIC), a Field Programmable Gate Array(FPGA), programmable logic device, chipset, application specificinstruction-set processor (ASIP), system-on-chip (SoC), centralprocessing unit (CPU) (e.g., one or multiple cores), microcontrollers,and/or other processing logic (e.g., embedded devices) capable ofcontrolling device 300 and/or executing programs/instructions.

Memory/storage 304 may include static memory, such as read only memory(ROM), and/or dynamic memory, such as random access memory (RAM), oronboard cache, for storing data and machine-readable instructions (e.g.,programs, scripts, etc.).

Memory/storage 304 may also include a floppy disk, CD ROM, CD read/write(R/W) disk, optical disk, magnetic disk, solid state disk, holographicversatile disk (HVD), digital versatile disk (DVD), and/or flash memory,as well as other types of storage device (e.g., Micro-Electromechanicalsystem (MEMS)-based storage medium) for storing data and/ormachine-readable instructions (e.g., a program, script, etc.).Memory/storage 304 may be external to and/or removable from networkdevice 300. Memory/storage 304 may include, for example, a UniversalSerial Bus (USB) memory stick, a dongle, a hard disk, off-line storage,a Blu-Ray® disk (BD), etc. Memory/storage 304 may also include devicesthat can function both as a RAM-like component or persistent storage,such as Intel® Optane memories.

Depending on the context, the term “memory,” “storage,” “storagedevice,” “storage unit,” and/or “medium” may be used interchangeably.For example, a “computer-readable storage device” or “computer-readablemedium” may refer to both a memory and/or storage device.

Input component 306 and output component 308 may receive input from auser and provide output to a user. Input/output components 306 and 308may include, for example, a display screen, a keyboard, a mouse, aspeaker, a microphone, a camera, a DVD reader, USB lines, and/or othertypes of components.

Network interface 310 may include a transceiver (e.g., a transmitter anda receiver) for network device 300 to communicate with other devicesand/or systems. For example, via network interface 310, network device300 may communicate over a network, such as the Internet, an intranet, aterrestrial wireless network (e.g., a WLAN, WiFi, WiMax, etc.), asatellite-based network, optical network, etc. Network interface 310 mayinclude a modem, an Ethernet interface to a LAN, and/or aninterface/connection for connecting device 300 to other devices (e.g., aBluetooth interface).

Communication path 312 may provide an interface (e.g., a bus) throughwhich components of device 200 can communicate with one another.

In some implementations, network device 300 may perform the operationsdescribed herein in response to processor 302 executing softwareinstructions stored in a non-transient computer-readable medium, such asmemory/storage 304. The software instructions may be read intomemory/storage 304 from another computer-readable medium or from anotherdevice via network interface 310. The software instructions stored inmemory/storage 304, when executed by processor 302, may cause processor302 to perform processes that are described herein. In otherimplementations, the instructions may be hard coded. For example, whennetwork device 300 is implemented as UE device 102, UE device 102 mayobtain HIP coordinates based on RACH signaling.

FIG. 4 illustrates exemplary functional components of UE device 102. Asshown, UE device 102 may include Timing Advance Determining logic 402, awireless station location database 404, and HIP-coordinates logic 406.Although UE device 102 may include other functional logic or components,they are not illustrated in FIG. 4 for simplicity. In otherimplementations, UE device 102 may include additional or differentfunctional components than those illustrated in FIG. 4 .

Timing Advance Determining logic 402 may include an applicationprogramming interface (API) for obtaining a value of the Timing Advanceparameter provided by wireless station 104. More specifically, whenHIP-coordinates logic 406 (or another component) calls Timing AdvanceDetermining logic 402, logic 402 may detect whether UE device 102 isperforming a RACH procedure. If UE device 102 is already engaged in sucha process, Timing Advance Determining logic 402 may look for a RandomAccess Response (RAR) message from wireless station 104. If there is noongoing RACH process, Timing Advance Determining logic 402 may cause UEdevice 102 to initiate a new RACH procedure. Thereafter, Timing AdvanceDetermining logic 402 may wait for a RAR message from wireless station104.

During a RACH procedure, when Timing Advance Determining logic detectsan incoming RAR message from wireless station 104, logic 402 may extractthe value of the Timing Advance parameter included the message. Afterverifying that the RAR message is intended for UE device 102, logic 402may return the Timing Advance parameter value to HIP-coordinates logic406. If logic 402 is unable to confirm that the RAR message is valid,logic 402 may re-initiate its attempt to obtain a Timing Advanceparameter value from wireless station 104.

Wireless station location database 404 may include a table, list, orrecords of coordinates of wireless stations 104. When HIP-coordinateslogic 406 needs coordinates of wireless station 104, HIP-coordinateslogic 406 may query database 404 with a key, such as an identifier forwireless station (e.g., Physical layer Cell Identifier (PCI)). Inresponse, database 404 may retrieve the coordinates corresponding to thewireless station 104 and provide the coordinates to logic 406. In someimplementations, the information in database 404 may have beendownloaded by HIP-coordinates logic 406 when UE device 102 registerswith provider network 202 for communication services.

HIP-coordinates logic 406 may determine high precision coordinates ofthe current location of UE device 102. When HIP-coordinates logic 406receives a request (e.g., from another application within UE device 102or from an external device) to provide UE device coordinates,HIP-coordinates logic 406 may call Timing Advance Determining logic 402,to obtain a value of Timing Advance parameter from a wireless station104. When Timing Advance Determining logic 402 provides at least threeTiming Advance parameter values corresponding to different wirelessstations 104, logic 406 may use each Timing Advance parameter value tocalculate a distance between UE device 102 and the correspondingwireless station 104. Logic 406 may then use the calculated distancesand coordinates of wireless stations 104 to determine UE device 102coordinates, via multilateration. HIP-coordinates logic 406 may obtainthe coordinates of wireless stations 104 from database 404.

FIGS. 5A-5C illustrate an exemplary process 500 for determining HIPcoordinates of UE device 102 based on RACH signaling according to oneimplementation. FIG. 6 is a messaging diagram illustrating an exemplaryRACH procedure. According to one embodiment, process 500 may beperformed by UE device 102.

Process 500 may start when UE device 102 decides that it needs todetermine its HIP coordinates. For example, HIP-coordinates logic 406may receive an API call from another program within UE device 102 toprovide HIP coordinates of UE device 102. In another example, UE device102 may receive a request from an external device to provide UE devicecoordinates.

Process 500 may include UE device 102 determining whether UE device 102can detect a sufficient number of wireless stations 104 to performmultilateration (block 502). For example, UE device 102 may be able todetect at least three wireless stations, based on different wirelessstation signals within a given area. If there are not enough wirelessstations 104 (block 502: NO), UE device 102 may terminate process 500.When UE device 102 terminates process 500, UE device 102 may provide,for example, an error message to a calling program or device. In anotherexample, assume that UE device 102 initiated process 500 to support anapplication launched by a user. UE device 102 may indicate that UEdevice 102 is unable to determine its HIP coordinates via its userinterface.

Process 500 may further include UE device 102 entering a RACH procedure(block 504), by either joining a RACH procedure currently in progress orby initiating a new RACH procedure.

As shown in FIG. 6 , prior to the start of a RACH procedure 603,wireless station 104 sends a downlink broadcast signal 602. Broadcastsignal 602 includes periodic radio frames, each of which occupies aparticular range of frequencies and spans a particular time interval.FIG. 7A shows exemplary radio frames 702-1, 702-2 . . . 702-M(collectively radio frames 702 and generically radio frame 702) ofbroadcast signal 602.

FIG. 7B illustrates an exemplary configuration of radio frame 702. Eachradio frame 702 comprises sub-frames 704-1 through 704-10. Sub-frames704 include information that UE device 102 needs for attaching toprovider network 202 via wireless station 104. In particular, each ofsub-frames 704 includes a Primary Synchronization Signal (PSS) 706 and asecondary Synchronization Signal (SSS) 708.

Returning to FIG. 5A, in response to broadcast signal 602, UE device 102detects broadcast signal 602, PSS 706 and SSS 708 (block 506). UE device102 can distinguish the beginning of each radio sub-frame 704, and thus,be able to synchronize to sub-frames 704.

PSS 706 and SSS 708 include information from which UE device 102 canderive an abbreviated Physical layer Cell Identity (PCI). Theabbreviated PCI is a short-hand notation for an identifier for wirelessstation 104. After UE device 102 detects PSS 706 and SSS 708, UE device102 derives the abbreviated PCI and stores the abbreviated PCI (block508).

In addition to PSS 706 and SSS 708, sub-frame 704 includes informationneeded by UE device 102 to continue with RACH procedure 603. Morespecifically, sub-frame 704 includes a System Information Block-2(SIB-2) that lists values of a number of parameters. For example, SIB-2may include information that designates a set of symbol sequences. UEdevice 102 may select a particular sequence from the set and send, towireless station 104, the sequence as part of a Physical Random AccessChannel (PRACH) preamble.

The selection of the preamble by UE device 102 may depend on the size ofa message that UE device 102 intends to send later. More specifically,if the size of a Radio Resource Control (RRC) connection request that UEdevice 102 wants to send later (see message 608 in FIG. 6 ) is greaterthan that specified in the SIB-2, UE device 102 would select the PRACHpreamble from a set referred to as Group B defined by 4G standards.Otherwise, UE device 102 would selects the PRACH preamble from Group A.

After UE device 102 selects a PRACH preamble, UE device 102 transmitsthe PRACH preamble in accordance with a predetermined format and timingrequirements specified by the SIB-2 (block 510 and PRACH preamble 604).

When wireless station 104 receives PRACH preamble 604, wireless station104 calculates what is known as a Random Access (RA)-Radio NetworkTemporary Identifier (RNTI) for UE device 102, based on the timing ofPRACH preamble 604. Thus, if two different UE devices 102 respond tobroadcast message 602 at the same time, by each sending a PRACHpreamble, wireless station 104 may generate the same RA-RNTI for both UEdevices 102. This introduces the potential for a contention between thetwo UE devices 102. The potential contention is discussed below withreference to FIG. 9 .

In addition to the RA-RNTI, wireless station 104 calculates TemporaryCell (TC)-RNTI and a value of a Timing Advance parameter. The parametervalue is computed based on the transmission time of broadcast signal 602and the time of receipt of PRACH preamble 604. Wireless station 104 thenbundles the RA-RNTI, the TC-RNTI, the value of the Timing Advanceparameter, and information needed by UE device 102 to send the nextuplink message to wireless station 104. Wireless station 104 sends thebundled information as a Radio Access Response (RAR) message 606 on aPhysical Downlink Shared Channel (PDSCH) to UE device 102.

Returning to FIG. 5A, process 500 includes UE device 102 receiving RARmessage 606 from wireless station 104 (block 512). When UE device 102receives RAR message 606, UE device 102 saves the TC-RNTI and makes atiming adjustment (block 514) in accordance with the value of the TimingAdvance parameter. The timing adjustment N_(T) is given by 16·(TimingAdvance parameter)·T_(S), where the value of the Timing Advanceparameter can range from 0 to 1282.

Network T_(S) is defined as 1/f/(DFT-size), where f is the subcarrierspacing and the DFT-size is the size of Discrete Fourier Transform inOrthogonal Frequency Division Multiplex (OFDM) transceivers.Accordingly, T_(S) may depend on the particular radio technology and thefrequency band involved in UE device communication. For example, for anLTE network, subcarrier spacing f may be 15 kHz and the DFT-size may be2048. Thus, T_(S)=1/(15000/2048)≈0.0325 μs. In another example, for aparticular 5G NR band, the DFT-size may be 4096, and the subcarrierspacing f may be 240 kHz. Thus, T_(S)=1/(240000/4096)≈1.02 nanoseconds.Other values of T_(S) are possible, depending on the radio accesstechnology.

The value of timing adjustment N_(T) is equal to twice the time delay Δbetween the transmission time of a message at wireless station 104 andthe time of its receipt at UE device 102. That is, N_(T)=2Δ. FIGS. 8A-8Dillustrate the time delay Δ. For FIGS. 8A and 8B, assume that a message(e.g., broadcast message 602) is transmitted from wireless station 104at T₀ and received by UE device 102 at T₀+Δ, where the time delay Δ is atravel time of the message over the distance between UE device 102 andwireless station 104. Assuming UE device 102 is temporarily synchronizedto the received message (i.e., synchronized to T₀+Δ), UE device 102would schedule the transmission of its next message to wireless station104 so that the next message is received by wireless station at time T₁.To do so, UE device 102 has to account for the time delay Δ of broadcastmessage 602 on its transit to UE device 102 and the same delay Δ of thenext message on its transmit to wireless station 104. Accordingly, UEdevice 102 has to advance the transmission time of its next message by2Δ, relative to the time of receipt. FIG. 8C illustrates advancing thetransmission time of its message by 2Δ=N_(T), such that, as shown inFIG. 8D, wireless station 104 receives the message at T₁.

Turning to FIG. 5B, process 500 includes UE device 102 storing the valueof the Timing Advance parameter (block 516). UE device 102 then selectsa random number as a temporary identifier, includes the temporaryidentifier in a RRC connection request 608 (block 518), and sends RRCconnection request 608 on a Physical Uplink Shared Channel (PUSCH) towireless station 104 (block 520).

When wireless station 104 receives RRC connection request 608, wirelessstation 104 extracts the random number included in RRC connectionrequest 608 and includes the random number as a validation code in a RRCconnection setup message 610 that wireless station 104 generates.Wireless station 104 then transmits RRC connection setup message 610 toUE device 102.

Process 500 further includes UE device 102 receiving RRC connectionsetup message 610 from wireless station 104 (block 522). UE device 102compares the validation code included by wireless station 104 in RRCconnection setup message 610 to the random number that UE device 102sent in RRC connection request 608 (block 524).

If the validation code does not match the random number (block 524: NO),UE device 102 determines that RAR message 606 to which UE device 102responded with RRC connection request 608 was not intended for UE device102, discards the stored value of Timing Advance parameter, andterminates the current RACH procedure (block 526). UE device 102 thenreturns to block 504 of process 500 to restart the RACH procedure 603.If the validation code does match the random number (block 524: YES),logic 406 retains the Timing Advance parameter value (block 528).

In process 500, the reason for performing blocks 518-526 is to resolveany signaling contention that can arise from another UE device 102engaged in a RACH procedure with wireless station 104. FIGS. 9A-9Dillustrate an exemplary contention between two UE devices 102 and 902attempting to attach to provider network 202 via wireless station 104.

In FIG. 9A, after wireless station 104 sends a broadcast message, UEdevice 102 and UE device 902 respond with a PRACH preamble messages904-1 and 904-2, respectively. Wireless station 104 accepts preamble904-1 but rejects preamble 904-2. In FIG. 9B, wireless station 104responds to preamble 904-1 by sending a RAR message 906 to UE device102. Because RAR message 906 is intended for UE device 102, RAR message906 includes a Timing Advance parameter value that pertains to UE device102. Both UE device 102 and UE device 902, however, receive RAR message906.

In FIG. 9C, UE device 102 responds to RAR message 906 with a RRCconnection request 908-1, which includes a random number A selected byUE device 102. UE device 902 responds to RAR message 906 with adifferent RRC connection request 908-2, which includes a random number Bselected by UE device 902. Wireless station 104, however, rejects RRCconnection request 908-2, because it has been time adjusted inaccordance with the Timing Advance parameter value that was provided inRAR message 906 for UE device 102.

In FIG. 9D, wireless station 104 sends a RRC connection setup message910 that includes the random number A as the validation code. Both UEdevices 102 and 902 receive message 910. When UE device 102 examines thevalidation code provided in RRC connection setup message 910, bycomparing it to the random number A, UE device 102 device confirms thatwireless station 104 has been corresponding with UE device 102. UEdevice 902 determines that wireless station 104 has not beencorresponding with UE device 902 but with UE device 102, because thevalidation code does not match the random number B. UE device 902 mayabandon the current RACH procedure and start a new RACH procedure withwireless station 104.

In some embodiments, UE device 102 may have the capability to avoidperforming blocks 518-526 to check for contention. More specifically,instead of performing all actions that are associated with RACHprocedure 603, UE device 102 may abort from RACH procedure 603 justafter block 516 (e.g., after UE device 102 receives RAR message 606 fromwireless station 104 and obtains the value of the Timing Advanceparameter). By terminating RACH procedure 603 just after block 516, UEdevice 102 may avoid burdening wireless station 104 with processing RRCconnection request 608 and sending RRC connection response message 610.This capability may be especially impactful in alleviating wirelessstations 104 load in wireless-station dense areas, because such areastypically have greatest traffic.

When UE device 102 does not complete full RACH procedure 603, the valueof the Timing Advance parameter that UE device 102 obtains may beincorrect. Wireless station 104 may have intended the Timing Advanceparameter value for a different UE device 102. However, whether UEdevice 102 further verifies the value by using other measurements (e.g.,measurements from additional wireless stations 104, values from its GPSreceivers, etc.) or using another method may be implementationdependent.

Turning to FIG. 5C, UE device 102 may determine whether there is a nextwireless station 104 for which UE device 102 is to determine the valueof the Timing Advance parameter (block 530). If so (block 530: YES), UEdevice 102 may proceed to block 504 to repeat the process 500 (exceptblock 502) for the next wireless station 104. Otherwise (block 530: NO),UE device 102 may use the values of the Timing Advance parameters toperform multilateration of the location of UE device 102 (block 532).

In performing the multilateration, UE device 102 calculates, for each ofthe Timing Advance parameter values, the distance between UE device 102and the corresponding wireless station 104 (block 532).

If D denotes the distance between UE device 102 and a particularwireless station 104, D=N_(T)·(Speed of Light)/2. For example, if thevalue of Timing Advance parameter is 1, then:

$\begin{matrix}{N_{T} = {16 \cdot \left( {{Timing}\mspace{14mu}{Advance}\mspace{14mu}{parameter}} \right) \cdot T_{S}}} \\{= {16 \cdot T_{S}}}\end{matrix}$

For example, for an LTE network, N_(T)=16·T_(S)=0.521 μs and D=[(0.52μs)·3×10⁸ m/s]/2≈78 m. In another example, for a 5G NR network, N_(T)=16T_(S)≈16 nanoseconds, and D=(N_(T)·3×10⁸ m/s)/2=8×10⁻⁹ s·3×10⁸ m/s=2.4m.

The multilateration further include UE device 102 using the calculateddistances to locate UE device 102. For example, assume that a particularS_(i) denotes a particular wireless station 104 (i=1, 2, 3 . . . ), andthe distance between the wireless station S_(i) and UE device 102 hasbeen determined as R_(i). If coordinates (x, y, z) denotes the unknownlocation of UE device 102 and (x_(i), y_(i), z_(i)) denotes the knownlocation of wireless station 104 S_(i), it is possible to write:(x−x _(i))²+(y−y _(i))²−(z−yz _(i))² =R _(i) ²  (1).

If there are three wireless stations S_(i), each for i=1, 2, and 3,then, expression (1) leads to:(x−x ₁)²+(y−y ₁)²+(z−yz ₁)² =R ₁ ²  (2)(x−x ₂)²+(y−y ₂)²+(z−yz ₂)² =R ₂ ²  (3)(x−x ₃)²+(y−y ₃)²+(z−yz ₃)² =R ₃ ²  (4)

Each of expressions (2)-(4) is an algebraic equation that describes athree-dimensional sphere in XYZ coordinates. FIG. 10 illustratesexemplary spheres corresponding to expressions (2)-(4). As shown, thevalues of x, y, and z that satisfy all expressions (2)-(4) occur at theintersection of the three spheres, and are the simultaneous solution ofexpressions (2)-(4).

Each of expressions (2)-(4) includes quadratic terms of x, y, and z.These quadratic terms in expressions (2)-(4) are identical. Thissuggests eliminating the quadratic terms to derive linear expressions ofx, y, and z, by subtracting one of expressions (2)-(4) from another oneof expressions (2)-(4). Accordingly, subtracting expression (3) from (2)and collecting terms yield:2x(x ₂ −x ₁)+x ₁ ² −x ₂ ²+2y(y ₂ −y ₁)+y ₁ ² −y ₂ ²+2z(z ₂ −z ₁)+z ₁ ²−z ₂ ² =R ₁ ² −R ₂ ²  (5)

Subtracting expression (4) from (3) and collecting terms yield:2x(x ₃ −x ₂)+x ₂ ² −x ₃ ²+2y(y ₃ −y ₂)+y ₂ ² −y ₃ ²+2z(z ₃ −z ₂)+z ₂ ²−z ₃ ² =R ₂ ² −R ₃ ²  (6)

Subtracting expression (4) from (2) and collecting terms yield:2x(x ₃ −x ₁)+x ₁ ² −x ₃ ²+2y(y ₃ −y ₁)+y ₁ ² y ₃ ²+2z(z ₃ −z ₁)+z ₁ ² −z₃ ² =R ₁ ² −R ₃ ²  (7).

Coordinates (x_(i), y_(i), z_(i)) for wireless stations S_(i) (i=1, 2,and 3) correspond to the locations of wireless stations 104.HIP-coordinates logic 406 can obtain the values of these coordinatesfrom wireless station location database 404, as discussed above. Also asdiscussed above, R_(i)s are calculated from the values of the TimingAdvance parameter. Thus, the only unknown values in expressions (5)-(7)are those of x, y, and z. Accordingly, expressions (5)-(7) are threelinear equations of three unknown variables, x, y, and z. Theseequations can be solved by applying one of many methods for solving asystem of linear equations (e.g., Gaussian elimination, Cramer's Rule,Cholesky Decomposition, Gauss-Jordan Elimination, Gauss-Seidel iterativemethod, etc.).

In a different embodiment, UE device 102 may obtain more than threevalues of the Timing Advance parameter, each from a different wirelessstation 104 (i.e., there are more than three wireless stations 104 forUE device 102 to perform multilateration). In this embodiment,performing the algebraic manipulations discussed above leads to morethan three linear equations. Since there are only three unknownvariables, the equations are over-determined. Accordingly, theleast-squares solution can be obtained for x, y, and z, where theaccuracy of x, y, and z depends on the number of measurements (i.e., thenumber of wireless stations 104). Increasing the number of values of theTiming Advance parameter increases the accuracy of the HIP coordinates(x, y, z) obtained as the least-squares solution.

In a different embodiment, instead of UE device 102 performing block532, UE device 102 may send the values of the Timing Advance parameterand its corresponding abbreviated PCIs to location service platform 106,which may be stationed in provider network 202. Location serviceplatform 106 may perform the multilateration based on the values ofTiming Advance parameter and the PCIs, and provide the HIP coordinatesof UE device 102 to subscribers. Location service platform 106 mayinclude its own wireless station location database, similar to database404 described for UE device 102.

In another embodiment, instead of performing block 502, UE device 102may proceed directly to block 504 to initiate RACH procedure 603. UEdevice 102 may count the number of wireless stations 104 with which UEdevice 102 it has performed RACH procedure 603 based on detectingdifferent PCIs. If UE device 102 is unable to perform sufficient numberof RACH procedures 603 with different wireless stations 104, UE device102 may indicate (to a user or to another device) that it is unable toobtain its HIP coordinates.

In this specification, various preferred embodiments have been describedwith reference to the accompanying drawings. It will be evident thatmodifications and changes may be made thereto, and additionalembodiments may be implemented, without departing from the broader scopeof the invention as set forth in the claims that follow. Thespecification and drawings are accordingly to be regarded in anillustrative rather than restrictive sense.

In the above, while a series of blocks have been described with regardto the processes illustrated in FIGS. 5A-5C, the order of the blocks maybe modified in other implementations. In addition, non-dependent blocksmay represent blocks that can be performed in parallel.

It will be apparent that aspects described herein may be implemented inmany different forms of software, firmware, and hardware in theimplementations illustrated in the figures. The actual software code orspecialized control hardware used to implement aspects does not limitthe invention. Thus, the operation and behavior of the aspects weredescribed without reference to the specific software code—it beingunderstood that software and control hardware can be designed toimplement the aspects based on the description herein.

Further, certain portions of the implementations have been described as“logic” that performs one or more functions. This logic may includehardware, such as a processor, a microprocessor, an application specificintegrated circuit, or a field programmable gate array, software, or acombination of hardware and software.

To the extent the aforementioned embodiments collect, store, or employpersonal information of individuals, it should be understood that suchinformation shall be collected, stored, and used in accordance with allapplicable laws concerning protection of personal information.Additionally, the collection, storage, and use of such information canbe subject to consent of the individual to such activity, for example,through well known “opt-in” or “opt-out” processes as can be appropriatefor the situation and type of information. Storage and use of personalinformation can be in an appropriately secure manner reflective of thetype of information, for example, through various encryption andanonymization techniques for particularly sensitive information.

No element, block, or instruction used in the present application shouldbe construed as essential to the implementations described herein unlessexplicitly described as such. As used herein, the articles “a,” “an,”and “the” are intended to include one or more items. The phrase “basedon” is intended to mean “based, at least in part, on” unless explicitlystated otherwise.

What is claimed is:
 1. A device comprising: an interface to communicatewith wireless stations in a network; and a processor configured to:perform a partial Random Access Chanel (RACH) procedure for eachwireless station of a plurality of wireless stations, wherein thepartial RACH procedure for each wireless station of the plurality ofwireless stations includes: starting a RACH procedure; selecting andtransmitting a Physical Random Access Channel (PRACH) preamble to thewireless station; receiving a Random Access Response (RAR) message fromthe wireless station; extracting a parameter value from the RAR message;storing the extracted parameter value; and terminating the RACHprocedure before completing the RACH procedure, wherein the deviceincludes a User Equipment (UE) device.
 2. The device of claim 1, whereinthe extracted parameter value includes: a value of a Timing Advanceparameter in the RAR message.
 3. The device of claim 1, wherein theprocessor is further configured to: determine a location of the devicebased on the extracted parameter values from performing, for each of theplurality of wireless stations, the partial RACH procedure.
 4. Thedevice of claim 3, wherein when the processor determines the location,the processor is configured to: apply multilateration based on theextracted parameter values.
 5. The device of claim 4, wherein when theprocessor applies multilateration, the processor is configured to:determine a distance from the device to each of the plurality ofwireless stations.
 6. The device of claim 1, wherein starting the RACHprocedure includes: detecting a broadcast signal from the wirelessstation.
 7. The device of claim 1, further comprising: verifying theextracted parameter value by using measurements from other wirelessstations.
 8. A method comprising: performing, by a User Equipment (UE)device, a partial Random Access Chanel (RACH) procedure for at least onewireless station of a plurality of wireless stations, wherein thepartial RACH procedure includes: starting a RACH procedure; selectingand transmitting a Physical Random Access Channel (PRACH) preamble tothe wireless station; receiving a Random Access Response (RAR) messagefrom the wireless station; extracting a parameter value from the RARmessage; storing the extracted parameter value; and terminating the RACHprocedure before completing the RACH procedure.
 9. The method of claim8, wherein the extracted parameter value includes: a value of a TimingAdvance parameter in the RAR message.
 10. The method of claim 8, furthercomprising: determining a location of the device based on the extractedparameter value and other values obtained from performing, for otherwireless stations of the plurality of wireless stations, the partialRACH procedure.
 11. The method of claim 10, wherein determining thelocation comprises: applying multilateration based on the extractedparameter values.
 12. The method of claim 11, wherein applyingmultilateration includes: determining a distance from the device to eachof the plurality of wireless stations.
 13. The method of claim 8,wherein starting the RACH procedure includes: detecting a broadcastsignal from the wireless station.
 14. The method of claim 8, furthercomprising: verifying the extracted parameter value by usingmeasurements from other wireless stations.
 15. A non-transitorycomputer-readable medium, including processor-executable instructionsthat, when executed by a processor included in a User Equipment (UE)device, cause the processor to: perform a partial Random Access Chanel(RACH) procedure for at least one wireless station of a plurality ofwireless stations, wherein the partial RACH procedure includes: startinga RACH procedure; selecting and transmitting a Physical Random AccessChannel (PRACH) preamble to the wireless station; receiving a RandomAccess Response (RAR) message from the wireless station; extracting aparameter value from the RAR message; storing the extracted parametervalue; and terminating the RACH procedure before completing the RACHprocedure.
 16. The non-transitory computer-readable medium of claim 15,wherein the extracted parameter value includes: a value of a TimingAdvance parameter in the RAR message.
 17. The non-transitorycomputer-readable medium of claim 15, wherein the processor is furtherto: determine a location of the device based on the extracted parametervalue and other values obtained from performing, for other wirelessstations of the plurality of wireless stations, the partial RACHprocedure.
 18. The non-transitory computer-readable medium of claim 17,wherein when the processor determines the location, the processor is to:apply multilateration based on the extracted parameter values.
 19. Thenon-transitory computer-readable medium of claim 18, wherein when theprocessor applies multilateration, the processor is to: determine adistance from the device to each of the plurality of wireless stations.20. The non-transitory computer-readable medium of claim 15, whereinstarting the RACH procedure includes: detecting a broadcast signal fromthe wireless station.